JN0-106 User Interfaces Practice Test 3 — 15 Questions

Question 1

An engineer needs to view the current operational state of the device, including system uptime, CPU load, and memory usage. Which two commands would provide this information? (Choose two.)

Accepted Answer

show system uptime. The 'show system uptime' command displays the system uptime, load averages, and current time, which directly provides the uptime and CPU load information. The 'show system memory' command shows memory usage statistics, including total, used, and available memory. Together, these two commands fulfill the requirement to view the current operational state including system uptime, CPU load, and memory usage.

Answer

show system processes

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show system storage

Answer

show chassis hardware

Question 2

A junior administrator is learning to navigate the Junos CLI. Which three statements about CLI modes are correct? (Choose three.)

Accepted Answer

Operational mode is indicated by a > prompt.. The Junos CLI uses the '>' character to indicate operational mode, which is the default mode for monitoring and troubleshooting the device. In this mode, you can execute commands like 'show' and 'ping' but cannot make configuration changes.

Answer

The 'commit' command is available in both operational and configuration modes.

Answer

You can switch from configuration mode to operational mode using the 'exit configuration' command.

Question 3

Which THREE statements about the Junos CLI help system are correct? (Choose three.)

Accepted Answer

Pressing completes the current keyword if unique.. The Junos CLI includes a tab-completion feature that, when you press the key, automatically completes the current keyword if it is unique within the current hierarchy level. This speeds up command entry and reduces typing errors, a standard behavior in Junos.

Answer

Pressing <Ctrl+P> clears the command line.

Answer

Pressing ? at the beginning of a line shows all commands regardless of the current hierarchy level.

Question 4

Refer to the exhibit. An administrator sees the following configuration output. What is the purpose of the 'description' statement in this context?

Accepted Answer

It sets the interface description visible in 'show interfaces description'.. In Junos, the 'description' statement under an interface configuration sets a text string that is displayed in the output of 'show interfaces description'. This is the standard way to provide a human-readable label for the interface, such as 'Link to Core Router A'. It does not affect SNMP, administrative comments, or syslog tags.

Answer

It sets the SNMP ifAlias to the interface's MAC address.

Answer

It sets the administrative comment visible in the config.

Answer

It sets the interface's syslog tag.

Question 5

Refer to the exhibit. An engineer notices high error counts on the interface. Based on the output, what is the most likely cause?

Accepted Answer

The interface is connected to a device configured for half-duplex.. The output shows high error counts on the interface, which is a classic symptom of a duplex mismatch. When one end of an Ethernet link operates in full-duplex and the other in half-duplex, collisions occur on the half-duplex side because it expects to wait for the carrier to be clear before transmitting, while the full-duplex side transmits at any time. This leads to frame check sequence (FCS) errors, alignment errors, and runts on the half-duplex interface. Option D is correct because the local interface is likely full-duplex (default on modern Juniper devices), and the connected device is configured for half-duplex, causing the mismatch.

Answer

The interface has a hardware fault.

Answer

The interface is experiencing excessive broadcasts.

Answer

The interface is operating in half-duplex mode.

Question 6

A network administrator has made several configuration changes and now wants to revert all uncommitted changes back to the last committed configuration. Which command should they use?

Accepted Answer

rollback 0. The 'rollback 0' command reverts all uncommitted changes and restores the active configuration to the last committed configuration. In Junos, candidate configurations are stored in numbered rollback slots (0 being the most recent committed configuration), so 'rollback 0' discards any uncommitted edits and loads the last committed state.

Answer

rollback 1

Answer

load override terminal

Answer

commit check

Question 7

An engineer wants to apply a candidate configuration and automatically revert to the previous configuration after 10 minutes if the commit is not confirmed. Which command should be used?

Accepted Answer

commit confirmed 10. The `commit confirmed 10` command commits the candidate configuration and starts a 10-minute timer. If the commit is not explicitly confirmed with another `commit` command within that time, Junos automatically reverts to the previous configuration. This is the correct method for a timed automatic rollback after a commit.

Answer

commit at 10

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set system commit timer 10

Answer

commit check

Question 8

A technician needs to display the contents of a configuration file stored on the device's hard disk. Which operational mode command should they use?

Accepted Answer

file show. The 'file show' command in Junos operational mode is used to display the contents of a file stored on the device's hard disk, such as a configuration file. Unlike 'show configuration', which displays the active candidate or committed configuration, 'file show' reads the raw file from the filesystem, making it the correct choice for viewing a stored configuration file.

Answer

show configuration

Answer

file list

Answer

view file

Question 9

An administrator is in configuration mode and wants to see only the interfaces configuration block while editing. Which command will display just that section?

Accepted Answer

show interfaces. In Junos configuration mode, the 'show interfaces' command displays only the interfaces configuration block without leaving configuration mode. This is a Junos-specific feature where 'show' commands within configuration mode show the current candidate configuration, not operational state. The command filters the output to show only the 'interfaces' hierarchy, allowing the administrator to review just that section.

Answer

show

Answer

display set | match interfaces

Answer

run show interfaces

Question 10

A junior engineer accidentally enters 'set interfaces ge-0/0/0 unit 0 family inet address 192.0.2.1/24' in operational mode. What will happen?

Accepted Answer

An error message is displayed, and no changes are made.. In Junos OS, the 'set' command is a configuration mode command used to modify the candidate configuration. When entered in operational mode (indicated by the '>' prompt), the CLI does not recognize it as a valid operational command. Junos will immediately display an error message such as 'unknown command' and make no changes to the running or candidate configuration.

Answer

The IP address is configured successfully.

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The command is queued for later execution.

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The CLI automatically switches to configuration mode.

Question 11

An engineer needs to check if a junos configuration file is syntactically correct before applying it. Which command should be used?

Accepted Answer

commit check. The 'commit check' command validates the syntax and semantics of the candidate configuration without applying it. If errors are found, they are reported, and the configuration is not committed. This allows the engineer to verify correctness before making the change active.

Answer

load check

Answer

check commit

Answer

validate

Question 12

A network engineer wants to see all commands entered in the current session. Which operational mode command should they use?

Accepted Answer

show cli history. 'show cli history' is the operational mode command in Junos that displays all commands entered during the current CLI session. This command retrieves the session-specific command history buffer, which is distinct from the system-wide history or shell history.

Answer

history

Answer

show commands

Answer

show system history

Question 13

An administrator is troubleshooting an interface and wants to see real-time packet statistics. Which command should they use?

Accepted Answer

monitor interface. The 'monitor interface' command in Junos provides real-time, continuously updated packet statistics for a specified interface, making it the correct choice for live troubleshooting. Unlike static commands, it refreshes statistics every second until interrupted, allowing the administrator to observe traffic patterns as they occur.

Answer

traceoptions

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show interfaces statistics

Answer

show interfaces extensive

Question 14

Which TWO commands can be used to view the current active configuration on a Junos device? (Choose two.)

Accepted Answer

show configuration | display set. The 'show configuration | display set' command displays the active configuration in a set-based format, which is a valid way to view the current active configuration on a Junos device. Option C is correct because the 'show configuration' command directly displays the active configuration in hierarchical format, which is the primary method to view the running configuration.

Answer

show system configuration

Answer

show | compare

Answer

show interfaces

Question 15

Which TWO statements are true about the 'commit confirmed' command? (Choose two.)

Accepted Answer

The default timeout is 10 minutes.. The default timeout for the 'commit confirmed' command in Junos is 10 minutes. If no confirmation commit is issued within that period, the system automatically rolls back to the previous configuration, ensuring network stability during remote changes.

Answer

It is used to schedule a commit at a future time.

Answer

It saves the configuration to a file before applying.

Answer

The timeout can be set only in multiples of 5 minutes.